The nuclear import receptor Kapβ2 modifies neurotoxicity mediated by poly(GR) in C9orf72-linked ALS/FTD

Expanded intronic G4C2 repeats in the C9ORF72 gene cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These intronic repeats are translated through a non-AUG-dependent mechanism into five different dipeptide repeat proteins (DPRs), including poly-glycine-arginine (GR), which is aggregation-prone and neurotoxic. Here, we report that Kapβ2 and GR interact, co-aggregating, in cultured neurons in-vitro and CNS tissue in-vivo. Importantly, this interaction significantly decreased the risk of death of cultured GR-expressing neurons. Downregulation of Kapβ2 is detrimental to their survival, whereas increased Kapβ2 levels mitigated GR-mediated neurotoxicity. As expected, GR-expressing neurons displayed TDP-43 nuclear loss. Raising Kapβ2 levels did not restore TDP-43 into the nucleus, nor did alter the dynamic properties of GR aggregates. Overall, our findings support the design of therapeutic strategies aimed at up-regulating Kapβ2 expression levels as a potential new avenue for contrasting neurodegeneration in C9orf72-ALS/FTD.

Hysteresis in phase volumes, compositions and interfacial roughness in model OPV-small-molecule/polymer thin-films

Domain morphology and composition, and the structure of interfaces between domains are key factors in the performance and stability of organic photovoltaics (OPVs) fabricated from polymer/small-molecule blends. In this study, we investigate the evolution of composition, phase-volume and interfacial roughness in model polymer/small-molecule bilayers, in response to thermal annealing. Polystyrene/fullerene mixing is studied as a function of annealing temperature, using in situ neutron reflectivity, in thin-film bilayer samples comprising pure component or mixed layers. Remarkably, we discover that thermal annealing at temperatures around or above the reported glass transition temperatures, Tg, of the components can result in extensive mass-transfer between layers, that has the superficial appearance of equilibration, but leaves the layer compositions, thicknesses, and/or the interfacial composition profile in a non-equilibrium state. This is not merely a case of slow kinetics near Tg, as subsequent heating to higher temperatures, followed by cooling, reveals pronounced hysteresis in these systems. This has important implications for the measurement of equilibrium compositions in polymer/small-molecule mixtures for OPV applications, and for device stability during operation.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Assessing the Concordance of MRSA Carriage Screening With MRSA Infections

OBJECTIVES

This study focused on children with confirmed methicillin-resistant Staphylococcus aureus (MRSA) infections to determine MRSA screening utility in guiding empirical anti-MRSA treatment of children without history of MRSA infection. We examined the concordance of screens to assess differences by infection type and used statistical analysis to determine significant contributors to concordance.

METHODS

Pediatric hospital patients admitted from 2002 through 2022 were included. Subjects had MRSA infections subsequent to MRSA surveillance screens performed the preceding year. Statistical analysis identified associations between MRSA screens and infections. Number needed to treat analysis calculated the utility of rescreening.

RESULTS

Among 246 subjects, 39.0% had concordant screens; 151 (61.4%) screens were obtained in the 2 weeks preceding infection. Sensitivity for bacteremia was 50.0% (n = 42), for endotracheal/respiratory 44.4% (n = 81), and 29.4% (n = 102) for skin and soft-tissue infection. For children aged younger than 6 months, sensitivity was 35.9% (n = 78). Multivariable analysis significantly associated days since screening with decreasing likelihood of concordance. Regression modeled the probability of concordance to drop below 50.0% for all infections after 4 days, after 6 days for bacteremia specifically, and 12 days for endotracheal/respiratory infections.

CONCLUSIONS

The concordance of screens was far lower than negative predictive values found previously; earlier studies were possibly impacted by low prevalence and exclusion of children at high risk to inform high negative predictive values. We suggest that negative MRSA screens should not invalidate reasonable suspicion for MRSA infection in patients with high pretest probabilities.

Neonatal Serum Gentamicin Concentrations and Outcomes Following Maternal Once-Daily Gentamicin Dosing

OBJECTIVE

This study evaluated newborn gentamicin serum concentrations after birth and the effects on the newborn after extended interval gentamicin dosing in peripartum mothers.

METHODS

This was a single-center, retrospective chart review of neonates born to mothers that received peripartum once-daily gentamicin dosing of approximately 5 mg/kg within 12 hours of delivery. A gentamicin serum concentration was obtained immediately after birth in the newborn. The primary outcome was initial neonatal gentamicin serum concentration after birth. Several secondary outcomes were evaluated including nephrotoxicity and ototoxicity. A subgroup analysis comparing baseline demographics of mother-newborn dyads with birth neonatal serum concentrations of less than 2 mcg/mL versus 2 mcg/mL or greater was performed.

RESULTS

A total of 32 mother-newborn dyads were included. Newborns had a median gestational age of 39.4 weeks and median birth weight of 3.4 kg. The mean initial gentamicin serum concentration was elevated at 3.1 ± 1.9 mcg/mL among all newborns. The median maternal dose based on actual body weight in newborns with gentamicin serum concentrations less than 2 mcg/mL was 3.5 (IQR, 3.3-4.8) mg/kg versus 4.8 (IQR, 4.3-5.2) mg/kg in those that had serum concentrations of 2 mcg/mL or greater (p = 0.025). All newborn gentamicin serum concentrations were less than 2 mcg/mL for maternal doses given less than 1 hour prior to delivery (n = 8). There were no significant differences in nephrotoxicity or ototoxicity.

CONCLUSIONS

Peripartum once daily dosing of gentamicin administered between 1 to 12 hours of birth may lead to clinically significant serum concentrations in newborns.

Urgent appeal to allow all professional nurses and midwives to prescribe pre-exposure prophylaxis (PrEP) in South Africa

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Towards optimal use of antithrombotic therapy of people with cancer at the end of life: A research protocol for the development and implementation of the SERENITY shared decision support tool

BACKGROUND

Even though antithrombotic therapy has probably little or even negative effects on the well-being of people with cancer during their last year of life, deprescribing antithrombotic therapy at the end of life is rare in practice. It is often continued until death, possibly resulting in excess bleeding, an increased disease burden and higher healthcare costs.

METHODS

The SERENITY consortium comprises researchers and clinicians from eight European countries with specialties in different clinical fields, epidemiology and psychology. SERENITY will use a comprehensive approach combining a realist review, flash mob research, epidemiological studies, and qualitative interviews. The results of these studies will be used in a Delphi process to reach a consensus on the optimal design of the shared decision support tool. Next, the shared decision support tool will be tested in a randomised controlled trial. A targeted implementation and dissemination plan will be developed to enable the use of the SERENITY tool across Europe, as well as its incorporation in clinical guidelines and policies. The entire project is funded by Horizon Europe.

RESULTS

SERENITY will develop an information-driven shared decision support tool that will facilitate treatment decisions regarding the appropriate use of antithrombotic therapy in people with cancer at the end of life.

CONCLUSIONS

We aim to develop an intervention that guides the appropriate use of antithrombotic therapy, prevents bleeding complications, and saves healthcare costs. Hopefully, usage of the tool leads to enhanced empowerment and improved quality of life and treatment satisfaction of people with advanced cancer and their care givers.

High Levels of Detection of Nonpneumococcal Species of Streptococcus in Saliva from Adults in the United States

While the sensitivity of detection of pneumococcal carriage can be improved by testing respiratory tract samples with quantitative PCR (qPCR), concerns have been raised regarding the specificity of this approach. We therefore investigated the reliability of the widely used lytA qPCR assay when applied to saliva samples from older adults in relation to a more specific qPCR assay (piaB). During the autumn/winter seasons of 2018/2019 and 2019/2020, saliva was collected at multiple time points from 103 healthy adults aged 21 to 39 (n = 34) and >64 (n = 69) years (n = 344 total samples). Following culture enrichment, extracted DNA was tested using qPCR for piaB and lytA. By sequencing the variable region of rpsB (S2 typing), we identified the species of bacteria isolated from samples testing lytA-positive only. While 30 of 344 (8.7%) saliva samples (16.5% individuals) tested qPCR-positive for both piaB and lytA, 52 (15.1%) samples tested lytA-positive only. No samples tested piaB-positive only. Through extensive reculture attempts of the lytA-positive samples collected in 2018/2019, we isolated 23 strains (in 8 samples from 5 individuals) that were also qPCR-positive for only lytA. Sequencing determined that Streptococcus mitis and Streptococcus infantis were predominantly responsible for this lytA-positive qPCR signal. We identified a comparatively large proportion of samples generating positive signals with the widely used lytA qPCR and identified nonpneumococcal Streptococcus species responsible for this signal. This highlights the importance of testing for the presence of multiple gene targets in tandem for reliable and specific detection of pneumococcus in polymicrobial respiratory tract samples. IMPORTANCE Testing saliva samples with quantitative PCR (qPCR) improves the sensitivity of detection of pneumococcal carriage. The qPCR assay targeting lytA, the gene encoding the major pneumococcal autolysin, has become widely accepted for the identification of pneumococcus and is even considered the "gold standard" by many. However, when applying this approach to investigate the prevalence of pneumococcal carriage in adults in New Haven, CT, USA, we identified nonpneumococcal Streptococcus spp. that generate positive signals in this widely used assay. By testing also for piaB (encoding the iron acquisition ABC transporter lipoprotein, PiaB), our findings demonstrate the importance of testing for the presence of multiple gene targets in tandem for reliable molecular detection of pneumococcus in respiratory tract samples; targeting only lytA may lead to an overestimation of true carriage rates.

Platelet response to influenza vaccination reflects effects of aging

Platelets are uniquely positioned as mediators of not only hemostasis but also innate immunity. However, how age and geriatric conditions such as frailty influence platelet function during an immune response remains unclear. We assessed the platelet transcriptome at baseline and following influenza vaccination in Younger (age 21-35) and Older (age ≥65) adults (including community-dwelling individuals who were largely non-frail and skilled nursing facility (SNF)-resident adults who nearly all met criteria for frailty). Prior to vaccination, we observed an age-associated increase in the expression of platelet activation and mitochondrial RNAs and decrease in RNAs encoding proteins mediating translation. Age-associated differences were also identified in post-vaccination response trajectories over 28 days. Using tensor decomposition analysis, we found increasing RNA expression of genes in platelet activation pathways in young participants, but decreasing levels in (SNF)-resident adults. Translation RNA trajectories were inversely correlated with these activation pathways. Enhanced platelet activation was found in community-dwelling older adults at the protein level, compared to young individuals both prior to and post-vaccination; whereas SNF residents showed decreased platelet activation compared to community-dwelling older adults that could reflect the influence of decreased translation RNA expression. Our results reveal alterations in the platelet transcriptome and activation responses that may contribute to age-associated chronic inflammation and the increased incidence of thrombotic and pro-inflammatory diseases in older adults.

P09.04.B The importance of treatment tolerability for people with glioma: registry review and qualitative findings from the COBra Study

Background

Gliomas are the commonest form of primary brain tumour, accounting for 80% of malignant brain tumours. Gliomas represent a heterogeneous group of cancers with variable outcomes, traditionally graded from I to IV (least to most aggressive). The poor prognosis of some glioma patients and high symptom burden has led to a growing emphasis on their quality of survival. Maintaining cognitive function, physical function and other health-related quality of life aspects throughout the disease trajectory are key considerations, particularly for patients with aggressive forms of glioma. It is therefore important that glioma intervention studies collect data aligned with patient priorities that enables assessment of the net clinical benefit of treatments and facilitates informed decision-making. In particular, and of increasing recognition, is the importance of monitoring the incidence of adverse events during and after the course of an intervention, and understanding their impact upon patients, and patients’ own assessment of, tolerability.

Material and Methods

A trial registry review, a systematic review of the qualitative literature and semi-structured interviews with patients and caregivers were undertaken. Outcomes were extracted from these sources to formulate a longlist during the development of a core outcome set for glioma interventional trials (the COBra study).

Results

The registry review (n=91), systematic review (n=21) and semi-structured interviews (n=19) identified many important outcomes and concepts, one of which was tolerability. Tolerability, adverse events, toxicity or safety was reported to be collected as an outcome in 46 trials. Outcomes related to tolerability were identified from 7 articles included in the systematic review. Themes related to tolerability emerged from the qualitative interviews. These included tolerability of side effects of treatment; trade-offs of side effects versus potential benefits in deciding on, and willingness to, undertake further treatment; and self-directed strategies for coping.

Conclusion

There is a growing acknowledgement of the importance of treatment tolerability in the wider field of cancer research. In glioma research specifically, its significance is yet to be reflected in outcomes collected in trials. Our qualitative findings indicate tolerability is of high significance to patients and those close to them. Participants reported how their preconceptions and experience of tolerability influenced treatment decisions and treatment uptake. However, outcomes related to tolerability were collected in just over half of trials in our sample. Tolerability and items relating to the patients’ experience of adverse events should be collected and reported in trial findings to reflect patients’ priorities and enable informed treatment decisions.

Phenotypes of disease severity in a cohort of hospitalized COVID-19 patients: Results from the IMPACC study

BACKGROUND

Better understanding of the association between characteristics of patients hospitalized with coronavirus disease 2019 (COVID-19) and outcome is needed to further improve upon patient management.

METHODS

Immunophenotyping Assessment in a COVID-19 Cohort (IMPACC) is a prospective, observational study of 1164 patients from 20 hospitals across the United States. Disease severity was assessed using a 7-point ordinal scale based on degree of respiratory illness. Patients were prospectively surveyed for 1 year after discharge for post-acute sequalae of COVID-19 (PASC) through quarterly surveys. Demographics, comorbidities, radiographic findings, clinical laboratory values, SARS-CoV-2 PCR and serology were captured over a 28-day period. Multivariable logistic regression was performed.

FINDINGS

The median age was 59 years (interquartile range [IQR] 20); 711 (61%) were men; overall mortality was 14%, and 228 (20%) required invasive mechanical ventilation. Unsupervised clustering of ordinal score over time revealed distinct disease course trajectories. Risk factors associated with prolonged hospitalization or death by day 28 included age ≥ 65 years (odds ratio [OR], 2.01; 95% CI 1.28-3.17), Hispanic ethnicity (OR, 1.71; 95% CI 1.13-2.57), elevated baseline creatinine (OR 2.80; 95% CI 1.63- 4.80) or troponin (OR 1.89; 95% 1.03-3.47), baseline lymphopenia (OR 2.19; 95% CI 1.61-2.97), presence of infiltrate by chest imaging (OR 3.16; 95% CI 1.96-5.10), and high SARS-CoV2 viral load (OR 1.53; 95% CI 1.17-2.00). Fatal cases had the lowest ratio of SARS-CoV-2 antibody to viral load levels compared to other trajectories over time (p=0.001). 589 survivors (51%) completed at least one survey at follow-up with 305 (52%) having at least one symptom consistent with PASC, most commonly dyspnea (56% among symptomatic patients). Female sex was the only associated risk factor for PASC.

INTERPRETATION

Integration of PCR cycle threshold, and antibody values with demographics, comorbidities, and laboratory/radiographic findings identified risk factors for 28-day outcome severity, though only female sex was associated with PASC. Longitudinal clinical phenotyping offers important insights, and provides a framework for immunophenotyping for acute and long COVID-19.

FUNDING

NIH.

287 Retrospective Review of a Single Surgeon 5-Year Experience of Paediatric Breast Reconstruction - Challenges, Experience, and the Increasing Role of Lipofilling

Aim

This case series reviews the presentation, clinical and surgical management of paediatric breast cases undertaken by a single surgeon. The series demonstrates the powerful role of lipomodelling when used with breast reshaping techniques to achieve good outcomes and avoid the need to commit young patients to breast implants.

Method

Retrospective analysis of paediatric breast referrals to a single surgeon at a regional plastic surgery breast reconstruction unit over a 5-year period.

Results

In a 5-year period, 15 cases which presented in childhood to a tertiary paediatric centre were referred on to our regional plastic surgery breast reconstruction unit. Two patients underwent correction of breast hypoplasia secondary to Poland's syndrome. Nine patients presented for breast asymmetry with associated tuberous deformity. One patient had maldevelopment of a breast secondary to a burn's contracture. Two patients presented with gigantomastia and one patient with juvenile fibroadenomas.

Conclusions

Paediatric breast abnormalities represent a small but important caseload for a breast reconstructive surgeon. This case series demonstrates the need for careful assessment and an individualised surgical plan for each patient. The surgical plan must achieve a satisfactory outcome whilst minimising the need for further procedures as the patient grows. It is the senior surgeon's preference to avoid breast implant-based reconstruction where possible. In all but one case lipomodelling combined with reshaping of the native tissue was used to good effect.

618 A Registrar - Delivered Urology Experience Improves Medical Student Knowledge of the Subject and Increases Interest in a Surgical Career

Introduction

Exposure to Urology is thought to vary considerably between medical schools, leading to a lack of competence by foundation doctors in basic urological skills and knowledge, and perhaps low interest in a urological / surgical career. In our hospital students had no dedicated Urology placement until 2020.

Method

A weeklong Urology placement was designed for 3rd year students. This comprised tutorials on topics set out by the university curriculum, a catheter insertion simulation session, and regular theatre and ward rounds. Most students also had the opportunity to insert a catheter on the ward / theatre. Students were encouraged to complete The National Catheter Education Programme, an online course providing a point for CST applications. This placement is registrar delivered, giving a more accurate idea of what a surgical career involves. Student feedback was obtained on the first and last days to ascertain self-rated confidence on a Likert-type scale regarding urological key topics, as well as career intentions.

Results

Self – rated knowledge on the 5 identified topics at the start of the week was most likely to be “Poor,” and by the end “Good” or “Very good.” By the end of the week most students indicated they were much more likely to pursue a career in surgery, although the same response was not seen as strongly for the subspeciality of Urology.

Conclusions

The placement continues to run and develop based on feedback. We look forward with interest to the publication of LEARN (uroLogical tEAching in bRitish medical schools Nationally) — a multicentre audit – to further inform this project.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

1151. Clinical Characteristics of Persistent Staph Aureus Bacteremia in Children

Background

Persistent Staphylococcus aureus bacteremia (pSAB) is a poorly defined entity, but associated with significant morbidity and mortality in children. We aim to better describe the epidemiological features of this clinical entity.

Methods

We performed a retrospective case series analysis of pediatric patients with pSAB at a single center children’s hospital using electronic medical data from 2016 – 2020. Bacterial persistence was defined as culture growth > 72 hours after first blood culture.

Results

Twenty-two patients with pSAB were included in the analysis. Sources of persistent infection were endovascular infection (n=11, 50%), osteoarticular infection (n=6, 27%,), isolated central line associated blood stream (n=4, 18%), isolated skin and soft tissue infection (n=2, 9%), and no known primary infectious site (n=1). Methicillin resistance occurred in 41% (n=9) of cases of pSAB. Total duration of therapy varied, with a median of 4 weeks from negative cultures (range of 2 – 8 weeks). Total days of positive cultures in pSAB were not significantly associated with methicillin susceptibility of the bacterial isolate, use of double gram-positive coverage, nor presence of a central venous catheter. Use of double gram-positive coverage occurred in 50% of cases with a mean duration of therapy of 11 days, most frequently in cases of septic thrombophlebitis (Table 1). Rifampin and gentamicin were the most commonly used agents.

Table 1. Clinical Characteristics of Children Treated with Double Gram-Positive Coverage

Conclusion

Children presenting with persistent S. aureus bacteremia present with a heterogenous group of underlying conditions and epidemiological features. While pediatric recommendations for double gram-positive coverage for synergy have not been established, their use for pSAB is common, especially in endovascular infections where culture persistence is often an expected outcome. Further research should examine risk factors for pSAB and define optimal treatment modalities and duration.

Disclosures

All Authors: No reported disclosures

1108. Evaluation of Vancomycin Dosing in Adolescents

Background

Pediatric vancomycin dosing varies based on age and renal function. Recent literature suggests previously recommended doses of 45-60 mg/kg/day may be insufficient to achieve an AUC:MIC ratio of 400-600 mg-hr/L and higher doses of at least 60 mg/kg/day may be required. However, data to guide dosing in adolescents is limited.

Methods

A single-center, retrospective chart review of patients aged 12 to 18 years who received vancomycin and had therapeutic drug monitoring (TDM) performed between July 2017 to June 2020 were included. The primary endpoint was the median total daily dose (TDD) of vancomycin required to achieve therapeutic serum concentrations. Secondary endpoints were to characterize how factors such as age, weight, trough versus AUC monitoring, malignancy, and trauma may influence dosing. The safety endpoint was the development of acute kidney injury (AKI).

Results

130 vancomycin courses in 86 patients were included. Baseline characteristics are presented in Table 1. Of the 130 vancomycin courses, 50 courses (38%) achieved therapeutic serum concentrations at a median TDD of 49.8 mg/kg/day (IQR 42 – 59.4). This was not statistically different from the sub- or supra-therapeutic groups (p=0.22). Based on age, the median TDD for 12-14 year olds was higher at 60 mg/kg/day (IQR 45-78.8; n=14) than for 15-16 and 17-18 year olds [45.3 mg/kg/day (IQR 41.1-51; n=15), 48 mg/kg/day (IQR 42-52; n=21), respectively]. Obese patients needed a median TDD of 43.5 mg/kg/day vs at least 51 mg/kg/day in healthy and overweight patients. Finally, AUC guided dosing resulted in a slightly lower overall median TDD vs trough guided dosing (45.8 mg/kg/day vs 50.5 mg/kg/day). Additional dose requirements based on age, weight, TDM and other characteristics are presented in Table 2. Of the 15 patients who developed AKI per pRIFILE criteria, 2 were classified as injury and 3 as failure.

Table 2. Total Daily Dose Course Analysis

Conclusion

To achieve therapeutic levels, adolescents 12 to14 years old need higher empiric doses of 60 mg/kg/day compared to 45 mg/kg/day in 15 to 18 year olds. Obese patients, however, may require lower TDD than underweight, healthy, and overweight patients. Patients that receive AUC versus trough monitoring may also require lower TDD to achieve therapeutic concentrations. More data is needed to further evaluate our findings.

Disclosures

All Authors: No reported disclosures

Reducing the use of empiric antibiotic therapy in COVID-19 on hospital admission

BACKGROUND

Empiric antibiotics for community acquired bacterial pneumonia (CABP) are often prescribed to patients with COVID-19, despite a low reported incidence of co-infections. Stewardship interventions targeted at facilitating appropriate antibiotic prescribing for CABP among COVID-19 patients are needed. We developed a guideline for antibiotic initiation and discontinuation for CABP in COVID-19 patients. The purpose of this study was to assess the impact of this intervention on the duration of empiric CABP antibiotic therapy among patients with COVID-19.

METHODS

This was a single-center, retrospective, quasi-experimental study of adult patients admitted between 3/1/2020 to 4/25/2020 with COVID-19 pneumonia, who were initiated on empiric CABP antibiotics. Patients were excluded if they were initiated on antibiotics > 48 h following admission or if another source of infection was identified. The primary outcome was the duration of antibiotic therapy (DOT) prior to the guideline (March 1 to March27, 2020) and after guideline implementation (March 28 to April 25, 2020). We also evaluated the clinical outcomes (mortality, readmissions, length of stay) among those initiated on empiric CABP antibiotics.

RESULTS

A total of 506 patients with COVID-19 were evaluated, 102 pre-intervention and 404 post-intervention. Prior to the intervention, 74.5% (n = 76) of patients with COVID-19 received empiric antibiotics compared to only 42% of patients post-intervention (n = 170), p < 0.001. The median DOT in the post-intervention group was 1.3 days shorter (p < 0.001) than the pre-intervention group, and antibiotics directed at atypical bacteria DOT was reduced by 2.8 days (p < 0.001). More patients in the post-intervention group were initiated on antibiotics based on criteria consistent with our guideline (68% versus 87%, p = 0.001). There were no differences between groups in terms of clinical outcomes.

CONCLUSION

Following the implementation of a guideline outlining recommendations for initiating and discontinuing antibiotics for CABP among COVID-19 inpatients, we observed a reduction in antibiotic prescribing and DOT. The guideline also resulted in a significant increase in the rate of guideline-congruent empiric antibiotic initiation.

Stability of SARS-CoV-2 RNA in Nonsupplemented Saliva

The expense of saliva collection devices designed to stabilize severe acute respiratory syndrome coronavirus 2 RNA is prohibitive to mass testing. However, virus RNA in nonsupplemented saliva is stable for extended periods and at elevated temperatures. Simple plastic tubes for saliva collection will make large-scale testing and continued surveillance easier.

1314. Neonatal Serum Gentamicin Concentrations following Maternal Once-daily Gentamicin Dosing

Background

Gentamicin is commonly used for peripartum infections. Given literature supporting efficacy of once-daily dosing (ODD) of 5 mg/kg for chorioamnionitis, University of Chicago Medicine made the change from three times daily dosing (TIDD) to ODD. As gentamicin readily cross the placenta, it would be expected that maternal ODD would result in higher gentamicin neonatal serum concentrations following birth.

Methods

This was a single-center, retrospective chart review of all neonates born to mothers receiving peripartum ODD gentamicin within 12 hours of delivery between October 2019 and March 2020. A STAT random gentamicin serum concentration was obtained upon admission in neonates when initiation of antibiotics was desired. Specific dosing recommendations (Table 1) were developed utilizing neonatal population-based pharmacokinetics. The primary outcome was initial neonatal gentamicin serum concentration at birth. Other outcomes were also evaluated. Results were evaluated in two groups based on neonatal serum concentrations of less than 2 mcg/mL (Group 1) versus 2 mcg/mL or greater (Group 2).

Table 1: Neonatal gentamicin dosing algorithm

Results

Thirty-two mother-newborn dyads were included in this study. Baseline demographics are shown in Table 2. Newborns had a median gestational age of 39.4 weeks and median birth weight of 3.39 kilograms. The mean initial gentamicin concentration was supratherapeutic at 3.06 + 1.92 mcg/mL among all newborns (Table 3). The mean maternal dose in Group 1 (n=11) was 3.52 mg/kg (3.34, 4.77) based on actual body weight and 4.78 mg/kg (4.34, 5.18) in Group 2 (n=21) (p=0.025). The median time between maternal gentamicin administration and time of delivery varied between the groups at 0.5 hours versus 2.63 hours, respectively (p=0.005). All newborn gentamicin concentrations were less than 2 mcg/mL for maternal doses given less than 1 hour prior to delivery (n=8) (Figure 1). Overall protocol compliance rate was 81.3%. There were no significant differences in nephrotoxicity or ototoxicity between groups.

Table 2. Baseline Demographics

Table 3. Outcomes

Figure 1. Comparison of maternal gentamicin time from administration to delivery and neonatal serum gentamicin concentrations

Conclusion

This study suggests peripartum ODD of gentamicin may lead to clinically significant serum concentrations in neonates if administered between 1 to 12 hours of birth. Further studies are warranted to evaluate the effects of maternal ODD of gentamicin on newborns.

Disclosures

All Authors: No reported disclosures

992. Rethinking the 28-day HIV nPEP Dispensing Practice: A Pediatric ID Clinic Analysis

Background

In July 2017, The University of Chicago Comer Children’s Hospital Emergency Department (ED) transitioned from a 5-day to a 28-day HIV nPEP (non-occupational post-exposure prophylaxis) dispensation model in an effort to increase adherence. Anecdotal reports of patients lost to follow-up after ED discharge called into question the utility and cost-effectiveness of this practice. We analyzed HIV nPEP follow-up rates in our clinic, explored reasons for nonadherence, and performed basic cost-savings analyses to inform potential changes to our dispensation model.

Methods

A retrospective review of both electronic health and pharmacy records was conducted for patients prescribed 28-days of HIV nPEP in the ED and scheduled for outpatient follow-up in Pediatric ID clinic from July 2017-June 2019. Clinic provider documentation of nPEP adherence and reasons for nonadherence were examined. Patients were given an initial dose of nPEP regimen in the ED and provided all subsequent doses to complete at home. Using average wholesale price (AWP), we calculated the total cost of each regimen and potential savings if a shorter duration of HIV nPEP supply was dispensed.

Results

50 patients received a 28-day supply of HIV nPEP. Please refer to Table 1 regarding baseline patient characteristics. Of these, only 19 (38%) patients had documented outpatient follow-up after nPEP initiation. Median time to follow-up was 6 days (IQR: 3.0-9.0 days). Of the 19 patients with follow-up, 3 admitted to medication non-adherence. Although side effects were elicited in a total of 9 patients (18%), only 1 cited medication intolerance as the reason for discontinuing their nPEP. Given the relatively short time to follow-up, a potential savings of $1720-2211/patient could be achieved if a 10-14 day supply was dispensed.

Conclusion

Outpatient follow-up after 28-day HIV nPEP dispensation in our ED was < 40%, calling into question the cost-effectiveness of this dispensation model. While our current practice alleviates nPEP interruption due to potential insurance issues and pick-up delays, follow-up and adherence are not assured. The significant cost-savings with a shorter supply at the outset may encourage more robust follow-up and adherence.

Disclosures

All Authors: No reported disclosures

Shifting sows: longitudinal changes in the periparturient faecal microbiota of primiparous and multiparous sows

Knowledge of periparturient longitudinal changes in sow microbiota composition is necessary to fully understand her role in the development of the piglet microbiota, but also to improve gut health and performance of the sow in lactation. Primiparous sows face the challenge of partitioning nutrients to support maternal growth in addition to supporting foetal growth and the demands of lactation. Additional metabolic stress present during the periparturient period may induce changes in the microbiota profile between primiparous and multiparous sows. Using 16S rRNA gene sequencing, the study aimed to characterise the longitudinal changes in the periparturient microbiota and identify differences within the sow microbiota profile associated with parity. Faecal samples from primiparous (n = 13) and multiparous (n = 16) sows were collected at four different time points (day -6, -1, 3 and 8) in relation to farrowing (day 0). Microbiota richness was lowest on day 3 and -1 of the periparturient period (P < 0.05). Microbiota community composition, assessed by weighted and unweighted UniFrac distances, demonstrated longitudinal changes, with day 3 samples clustering away from all other sampling time points (P < 0.05). The relative abundance of several genera segregated gestation from lactation samples including Roseburia, Prevotella 1, Prevotella 2, Christensenellaceae R-7 group, Ruminococcaceae UCG-002 and Ruminococcaceae UCG-010 (P < 0.01). Furthermore, day 3 was characterised by a significant increase in the relative abundance of Escherichia/Shigella, Fusobacterium and Bacteroides, and a decrease in Alloprevotella, Prevotellaceae UCG-003 and Ruminococcus 1 (P < 0.001). Primiparous sows had overall lower periparturient microbiota diversity (P < 0.01) and there was a significant interaction between parity and sampling time point, with primiparous sows having lower microbiota richness on day -6 (P < 0.001). There was a significant interaction between sow parity and sampling time point on microbiota composition on day -6 and -1 (unweighted UniFrac distances;  ≤ 0.01) and day 8 (weighted and unweighted UniFrac distances; P < 0.05). Whilst no significant interactions between sow parity and sampling day were observed for genera relative abundances, multiparous sows had a significantly higher relative abundance of Bacteroidetes dgA-11 gut group and Prevotellaceae UCG-004 (P < 0.01). This study demonstrates that the sow microbiota undergoes longitudinal changes, which are collectively related to periparturient changes in the sow environment, diet and physiological changes to support foetal growth, delivery and the onset of lactation, but also sow parity.

SalivaDirect: A simplified and flexible platform to enhance SARS-CoV-2 testing capacity

Background

Scaling SARS-CoV-2 testing to meet demands of safe reopenings continues to be plagued by assay costs and supply chain shortages. In response, we developed SalivaDirect, which received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA).

Methods

We simplified our saliva-based diagnostic test by (1) not requiring collection tubes with preservatives, (2) replacing nucleic acid extraction with a simple enzymatic and heating step, and (3) testing specimens with a dualplex qRT-PCR assay. Moreover, we validated SalivaDirect with reagents and instruments from multiple vendors to minimize supply chain issues.

Findings

From our hospital cohort, we show a high positive agreement (94%) between saliva tested with SalivaDirect and nasopharyngeal swabs tested with a commercial qRT-PCR kit. In partnership with the National Basketball Association (NBA) and National Basketball Players Association (NBPA), we tested 3,779 saliva specimens from healthy individuals and detected low rates of invalid (0.3%) and false-positive (<0.05%) results.

Conclusions

We demonstrate that saliva is a valid alternative to swabs for SARS-CoV-2 screening and that SalivaDirect can make large-scale testing more accessible and affordable. Uniquely, we can designate other laboratories to use our sensitive, flexible, and simplified platform under our EUA (https://publichealth.yale.edu/salivadirect/).

Funding

This study was funded by the NBA and NBPA (N.D.G.), the Huffman Family Donor Advised Fund (N.D.G.), a Fast Grant from Emergent Ventures at the Mercatus Center at George Mason University (N.D.G.), the Yale Institute for Global Health (N.D.G.), and the Beatrice Kleinberg Neuwirth Fund (A.I.K.). C.B.F.V. is supported by NWO Rubicon 019.181EN.004.

Frequent testing is critical to limit SARS-CoV-2 transmission. In response to this need, we developed SalivaDirect, a sensitive, simplified, and flexible testing framework, which received Emergency Use Authorization (EUA) from the U.S. Food and Drug Administration (FDA). We tested saliva collected from a hospital cohort and showed a high positive agreement (94%) as compared to paired nasopharyngeal swabs tested with a commercial diagnostic kit. Then, we partnered with the National Basketball Association (NBA) to test a large cohort of mostly healthy individuals, and we detected low rates of invalid (0.3%) and false-positive (0.03%–0.05%) results. Our study shows that SalivaDirect can help to increase testing capacity by providing access to an affordable framework that is less prone to supply chain shortages.

Simply saliva: stability of SARS-CoV-2 detection negates the need for expensive collection devices

Most currently approved strategies for the collection of saliva for COVID-19 diagnostics require specialized tubes containing buffers promoted for the stabilization of SARS-CoV-2 RNA and virus inactivation. Yet many of these are expensive, in limited supply, and not necessarily validated specifically for viral RNA. While saliva is a promising sample type as it can be reliably self-collected for the sensitive detection of SARS-CoV-2, the expense and availability of these collection tubes are prohibitive to mass testing efforts. Therefore, we investigated the stability of SARS-CoV-2 RNA and infectious virus detection from saliva without supplementation. We tested RNA stability over extended periods of time (2-25 days) and at temperatures representing at-home storage and elevated temperatures which might be experienced when cold chain transport may be unavailable. We found SARS-CoV-2 RNA in saliva from infected individuals is stable at 4°C, room temperature (~19°C), and 30°C for prolonged periods and found limited evidence for viral replication in saliva. This work demonstrates that expensive saliva collection options involving RNA stabilization and virus inactivation buffers are not always needed, permitting the use of cheaper collection options. Affordable testing methods are urgently needed to meet current testing demands and for continued surveillance in reopening strategies.

International multicentre review of perioperative management and outcome for catecholamine-producing tumours

BACKGROUND

Surgery for catecholamine-producing tumours can be complicated by intraoperative and postoperative haemodynamic instability. Several perioperative management strategies have emerged but none has been evaluated in randomized trials. To assess this issue, contemporary perioperative management and outcome data from 21 centres were collected.

METHODS

Twenty-one centres contributed outcome data from patients who had surgery for phaeochromocytoma and paraganglioma between 2000 and 2017. The data included the number of patients with and without α-receptor blockade, surgical and anaesthetic techniques, complications and perioperative mortality.

RESULTS

Across all centres, data were reported on 1860 patients with phaeochromocytoma or paraganglioma, of whom 343 underwent surgery without α-receptor blockade. The majority of operations (78·9 per cent) were performed using minimally invasive techniques, including 16·1 per cent adrenal cortex-sparing procedures. The cardiovascular complication rate was 5·0 per cent overall: 5·9 per cent (90 of 1517) in patients with preoperative α-receptor blockade and 0·9 per cent (3 of 343) among patients without α-receptor blockade. The mortality rate was 0·5 per cent overall (9 of 1860): 0·5 per cent (8 of 517) in pretreated and 0·3 per cent (1 of 343) in non-pretreated patients.

CONCLUSION

There is substantial variability in the perioperative management of catecholamine-producing tumours, yet the overall complication rate is low. Further studies are needed to better define the optimal management approach, and reappraisal of international perioperative guidelines appears desirable.

IgM ANCA in healthy individuals and in patients with ANCA-associated vasculitis

Low levels of IgM auto-antibodies have been reported in health and disease. IgM anti-neutrophil cytoplasmic antibodies (ANCA) have been reported in patients with ANCA-associated vasculitis (AAV). We sought to investigate if healthy individuals may have IgM ANCA in their sera. The first aim of the study was to determine whether IgM ANCA was present in healthy individuals and in patients with ANCA-associated vasculitis. The second aim was to determine what happens to IgM ANCA levels over time. The third aim was to determine whether bacterial infections affected IgM ANCA levels in non-AAV patients. Sera from healthy individuals and patients with AAV were tested for IgM ANCA by immunofluorescence on fixed neutrophils, immunoprecipitation, Western blot and ELISA. Peripheral blood mononuclear cells were isolated and tested by ELISpot for circulating IgM ANCA B cells. To determine whether infection affected IgM ANCA levels, we studied non-AAV patients with bacterial endocarditis or Staphylococcus aureus bacteraemia and measured IgM ANCA levels over time. IgM ANCA is detectable in both healthy individuals and patients with AAV and the titres decreased with increasing age. Circulating IgM ANCA B cells were identified by ELISpot. In the presence of infection, we could not find a significant change in IgM ANCA levels. We report the presence of low-level specific IgM ANCA in the sera of healthy individuals and in patients with ANCA-associated vasculitis. Bacterial infection did not affect the level of IgM ANCA in this small study.

The ALERT-B questionnaire: A screening tool for the detection of gastroenterological late effects after radiotherapy for prostate cancer

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ALERT-B provides an effective screening tool for gastroenterological late effects.

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84.4% and 95.7% of patients demonstrated complications at 6 and 12 months post-treatment.

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ROC curves at baseline indicated an AUC of 0.867 compared to the GSRS diarrhoea subscale.

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ROC curves at baseline indicated an AUC of 0.765 compared to the EPIC bowel subscale.

There is an increasing need to measure treatment-related side effects in normal tissues following cancer therapy. The ALERT-B (Assessment of Late Effects of RadioTherapy - Bowel) questionnaire is a screening tool that is composed of four items related specifically to bowel symptoms. Those patients that respond with a “yes” to any of these items are referred on to gastroenterologist in order to improve the long-term consequences of these side effects of radiological treatment. Here we wish to test the ability of this questionnaire to identify these subsequent gastroenterological complications by tracking prostate cancer patients that were positive with respect to ALERT-B. We also carry out receiver-operator curve (ROC) analysis for baseline data for an overall ALERT-B questionnaire score with respect to subscale data for the Gastrointestinal Symptom Rating Scale (GSRS) and the Expanded Prostate Cancer Index Composite (EPIC-26) questionnaire. 84.4% and 95.7% of patients identified by the ALERT-B questionnaire demonstrated complications diagnosed at 6 and 12 months post-treatment, respectively. ROC curve analysis of baseline data showed that ALERT-B detected clinically relevant levels of side effects established at baseline by the GSRS diarrhoea subscale (AUC = 0.867, 95% CI = 0.795 to 0.926) and at the minimally important level of side effects for the EPIC bowel subscale (AUC = 0.765, 95% CI = 0.617 to 0.913). These results show that ALERT-B provides a simple and effective screening tool for identifying gastroenterological complications after treatment for prostate cancer.

Study of 3He(n,p)3H reaction at cosmological energies with trojan horse method

In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.

1552. Correlation Between Vancomycin Serum Trough Concentrations and Area Under the Curve in Pediatric Patients

Background

Despite years of experience with vancomycin (VAN), the optimal method to monitor VAN therapy in pediatric patients is still unknown. Recent pediatric data indicate serum trough concentrations lower than 10–20 mg/L or 15–20 mg/L based on indication may achieve an AUC₂₄> 400 mg hours/L. The primary study objective was to compare AUC₂₄ to goal VAN serum trough concentrations (STC).

Methods

A retrospective chart review of pediatric patients who received intravenous VAN June 1, 2018 to December 31, 2018 was completed. AUC₂₄ was calculated using a trapezoidal method with 2 steady-state serum concentrations. A serum peak concentration was drawn 1 hour and 15 minutes following the end of infusion and an STC was drawn 30 minutes prior to infusion.

Results

During 25 admissions, 12 patients had a first AUC₂₄ at goal and 13 patients had a first AUC₂₄ below goal. Of 41 AUC₂₄ calculations, 27 AUC₂₄s were ≥400 mg hours/L (group 1), and 14 AUC₂₄s were <400 mg hours/L (group 2). Median AUC₂₄ was 561 mg hours/L for group 1 vs. 344.5 mg hours/L for group 2 (P < 0.001). Correlating Cmin and Ctrough (Ctr) for group 1 and group 2 were 12 mg/L and 13.5 mg/L vs. 6.4 mg/L and 7.3 mg/L, respectively (P < 0.001). Figure 1 shows the pharmacokinetic parameters for each group. Spearman correlation between AUC₂₄ and Cmin was 0.87. Of the 35 subtherapeutic VAN STCs, 20 (57.1%) achieved an AUC₂₄ ≥400 mg hours/L (P = 0.08). Subgroup analysis of AUC₂₄ 400–600 mg hours/L showed a median AUC₂₄ of 519 mg hours/L with correlating Cmin and Ctr of 10.6 mg/L and 11.9 mg/L, respectively. The MIC was <1 in 90.9% of cases (Figure 2). The mean VAN dose required to achieve an AUC₂₄ ≥400 mg hours/L was 77.7 mg/kg/day; dosing frequency did not appear to affect AUC₂₄ outcome. Time to culture clearance was 2 days in group 1 and 6.5 days in group 2 (P = 0.24). No cases of nephrotoxicity were identified despite AUC₂₄ values ranging from 265–1294 mg hours/L.

Conclusion

AUC₂₄ monitoring using a 2-sample trapezoidal method was successfully implemented at this institution. The results of this study align with previous pediatric studies, supporting the use of lower serum trough concentration goals of 10–15 mg/L.

Disclosures

All authors: No reported disclosures.

Hg-supported phospholipid monolayer as rapid screening device for low molecular weight narcotic compounds in water

This study positions the fabricated Pt/Hg-supported phospholipid sensor element in the context of more conventional biomembrane-based screening platforms. The technology has been used together with immobilised artificial membrane (IAM) chromatography and COSMOmic simulation methods to screen the interaction of a series of low molecular weight narcotic organic compounds in water with phosphatidylcholine (PC) membranes. For these chemicals it is shown that toxicity to aquatic species is related to compound hydrophobicity which is associated with compound accumulation in the phospholipid membrane as modelled by IAM chromatography measurements and COSMOmic simulations. In contrast, the Hg-supported dioleoyl phosphatidylcholine (DOPC) sensor element records membrane damage/modification which is indirectly related to general toxicity and directly related to compound structure. Electrochemical limit of detection (LoD) values depend on molecular structure and range from 20 μmolL^-1 for substituted phenols to 23 mmolL^-1 for aliphatics. Rapid cyclic voltammetry (RCV) "fingerprints" showed that the major structural classes of compounds: alkyl/chlorobenzenes, substituted phenols, quaternary ammonium compounds and neutral amines interacted distinctively with the DOPC on Hg and that these observations correlated with and supported those predicted by the COSMOmic simulations of the compound/DMPC association. In addition, the compatibility of the electrochemical and COSMOmic methods validates the electrochemical device as a meaningful high throughput technology to screen compounds in water and report on the mechanistic details of their interaction with phospholipid layers.

Bacillus subtilis 29784 induces a shift in broiler gut microbiome toward butyrate-producing bacteria and improves intestinal histomorphology and animal performance

The study reports the effects of Bacillus subtilis 29784 on broiler performance. A total of 1,600 one-day-old Cobb 500 male broiler chicks received either a control diet or the same diet to which B. subtilis 29784 spores were added (1E8 CFU/kg of feed). The birds were slaughtered at 42 D of age. Ileal and cecal tissues and content were collected for histomorphological analysis and 16S rRNA gene sequencing, respectively. The inclusion of B. subtilis 29784 led to an increase of final body weight gain of broilers (+5.7%; P < 0.0001) and an improvement in feed conversion ratio (-5.4%; P < 0.0001). Higher feed efficiency in the Bacillus-fed group was correlated with a significant increase in intestinal microvilli length (+18% in ileum and +17% in cecum; P < 0.001). Among the differences revealed by 16S rRNA analysis, Ruminococcus, Lachnoclostridium, and Anaerostipes were found in higher relative abundance in Bacillus-treated birds at the cecal level. These bacterial genera include species that produce butyrate, the main source of energy for enterocytes and known to be an immune modulator. There was also a slight increase in the Butyrivibrio genus in the cecum, which is known to be an important player in the production of conjugated linoleic acid, also considered an anti-inflammatory compound. In conclusion, dietary supplementation of B. subtilis 29784 significantly improved the growth performance of broilers, likely through beneficial effects on microbiota and host.

Abstract 4972: Preclinical development of a first-in-class NKp30xBCMA NK cell engager for the treatment of multiple myeloma

Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells. Although several new drugs for the treatment of MM have greatly improved survival, many patients are known to relapse and become refractory to all presently available therapies or experience treatment-related toxicities. Therefore, MM remains an unmet medical need and the development of additional novel therapies is required. NK cells play a crucial role in the control of multiple myeloma and accumulating evidence shows the presence of highly cytotoxic NK cells in the bone marrow of MM patients suggesting that targeting NK cells could provide a specific treatment modality to leverage NK cell cytotoxicity in myeloma. Furthermore, NK cells are the first lymphocytes population to reconstitute after autologous stem cell transplant (ASCT) providing an opportunity to target minimal residual disease (MRD) shortly after transplant. B-cell maturation antigen (BCMA) is an excellent target in MM because its restricted expression in normal and malignant plasma cells from untreated and relapsed myeloma patients, but absent in all other main bone marrow cell subsets. Our first-in-class NKp30xBCMA NK cells engager, CTX-4419, binds to BCMA on MM cells and to NKp30 and CD16A (FcγRIIIA) on NK cells, specifically redirecting NK cells towards tumor cells expressing BCMA. We demonstrate here that CTX-4419 retains activity in the presence of high levels of BCMA ligands and serum IgG and induces potent NK cytotoxicity against high and low BCMA expressing cell lines as well as patients (autologous) primary myeloma cells. Moreover, CTX-4419 does not require CD16A binding to kill tumor cells, a unique characteristic that overcomes the reduction or loss of activity of CD16A due to receptor shedding or downregulation in the tumor microenvironment. Furthermore CTX-4419 induces NK proliferation and cytokines/chemokines production by NK cells only in the presence of tumor cells providing sustainable anti-tumor specificity to NK cells. CTX-4419 activates in-vitro cynomolgus NK cells in presence of target cells expressing cynomolgus BCMA and, when given intravenously, CTX-4419 decreases plasma cell counts. CTX-4419 represents a novel class of NK-cell engagers that shows strong potency even in the absence of CD16A engagement and induces NK cell proliferation and lysis of tumor cells expressing low amount of antigen. CTX-4419 has strong activity in an autologous setting when tested in bone marrow samples of MM patients and shows efficacy in a non-human primate model of plasma-cell depletion. These data show that CTX-4419 is strongly differentiated from conventional therapeutic antibodies and is a promising candidate for MM treatment with the potential to be used as monotherapy or in combination with adoptive transfer of NK cells and/or other immuno-therapies.

Citation Format: Monia Draghi, Jamie L. Schafer, Allison Nelson, Zach Frye, Amanda Oliphant, Sara Haserlat, jason Lajoie, Kenneth rogers, Francois Villinger, Michael Schmidt, Robert Tighe, Piotr Bobrowicz, Jennifer Watkins-Yoon, Thomas Schuetz. Preclinical development of a first-in-class NKp30xBCMA NK cell engager for the treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4972.

Mucosal lactoferrin response to genital tract infections is associated with iron and nutritional biomarkers in young Burkinabé women

BACKGROUND/OBJECTIVES

The iron-binding affinity of vaginal lactoferrin (Lf) reduces iron available to genital pathogens. We describe host reproductive, nutritional, infection and iron biomarker profiles affecting vaginal Lf concentration in young nulliparous and primigravid women in Burkina Faso.

SUBJECTS/METHODS

Vaginal eluates from women who had participated in a randomized, controlled periconceptional iron supplementation trial were used to measure Lf using a competitive double-sandwich ELISA. For this analysis samples from both trial arms were combined and pregnant and non-pregnant cohorts compared. Following randomization Lf was measured after 18 months (end assessment) for women remaining non-pregnant, and at two antenatal visits for those becoming pregnant. Associations between log Lf levels and demographic, anthropometric, infection and iron biomarker variables were assessed using linear mixed models.

RESULTS

Lf samples were available for 712 non-pregnant women at end assessment and for 303 women seen at an antenatal visit. Lf concentrations of pregnant women were comparable to those of non-pregnant, sexually active women. Lf concentration increased with mid-upper-arm circumference, (P = 0.047), body mass index (P = 0.018), Trichomonas vaginalis (P < 0.001) infection, bacterial vaginosis (P < 0.001), serum C-reactive protein (P = 0.048) and microbiota community state types III/IV. Adjusted Lf concentration was positively associated with serum hepcidin (P = 0.047), serum ferritin (P = 0.018) and total body iron stores (P = 0.042). There was evidence that some women maintained persistently high or low Lf concentrations from before, and through, pregnancy.

CONCLUSION

Lf concentrations increased with genital infection, higher BMI, MUAC, body iron stores and hepcidin, suggesting nutritional and iron status influence homeostatic mechanisms controlling vaginal Lf responses.